Disclosed are dielectric cavity arrays with cavities formed by pairs of dielectric tips, wherein the cavities have low mode volume (e.g., 7*10.sup.−5λ.sup.3, where X is the resonance wavelength of the cavity array), and large quality factor Q (e.g., 10.sup.6 or more). Applications for such dielectric cavity arrays include, but are not limited to, Raman spectroscopy, second harmonic generation, optical signal detection, microwave-to-optical transduction, and as light emitting devices.

Fiber optic amplification includes a photonic crystal fiber coupled to a pump laser through a first coupler. The pump laser emits a first electromagnetic radiation wave into the photonic crystal fiber at a first oscillation frequency and a second electromagnetic radiation wave into the photonic crystal fiber at a second oscillation frequency equaling the first oscillation frequency. The first and second electromagnetic radiation waves interact to generate a signal comprising an electromagnetic radiation wave at a third oscillation frequency and an idler comprising a fourth electromagnetic radiation wave at a fourth oscillation frequency to be generated and amplified through parametric amplification. Parametric amplification is achieved by four wave mixing. The photonic crystal fiber emits a parametric output signal based on the four wave mixing. A nonlinear crystal frequency doubles the parametric output signal through second-harmonic generation.

An optical amplifier of the present disclosure includes a Raman amplification unit and a parametric amplification unit that is configured of a second-order nonlinear element including a PPLN waveguide. In the optical amplifier, second harmonic lights are generated from a fundamental wave light having a wavelength that is slightly detuned to a shorter wavelength side with respect to a phase matching wavelength of the second-order nonlinear element, and is utilized as excitation light for the parametric amplification unit. By utilizing the excitation light based on the fundamental wave light of the wavelength detuned from the phase matching wavelength, a phase matching curve can be obtained in a wide band in a difference frequency generation (DFG) process of the second-order nonlinear element. The reduction in conversion efficiency of the wavelength near the excitation light in the parametric amplification unit is compensated by the Raman amplification unit.

A dielectric-grating waveguide free-electron laser device generating coherent or laser-like radiation is provided. An electron beam propagates next to a dielectric waveguide with a built-in grating structure to generate highly confined coherent or laser-like radiation in the waveguide through the Bragg resonance, the backward-wave resonance, or the Fabry-Perot resonance provided by the grating-waveguide structure. The dielectric-grating waveguide can be made of linear optical materials or nonlinear optical materials or combination of linear and nonlinear optical materials to enable versatile functionalities, such as laser generation, laser-wavelength conversion, and laser signal processing. Owing to the build-up of the laser modes inside the dielectric waveguide, coherent or laser-like Smith-Purcell radiation is also generated above the grating via coupling and bunching of the electrons with the surface mode fields.

A dielectric-grating waveguide free-electron laser device generating coherent or laser-like radiation is provided. An electron beam propagates next to a dielectric waveguide with a built-in grating structure to generate highly confined coherent or laser-like radiation in the waveguide through the Bragg resonance, the backward-wave resonance, or the Fabry-Perot resonance provided by the grating-waveguide structure. The dielectric-grating waveguide can be made of linear optical materials or nonlinear optical materials or combination of linear and nonlinear optical materials to enable versatile functionalities, such as laser generation, laser-wavelength conversion, and laser signal processing. Owing to the build-up of the laser modes inside the dielectric waveguide, coherent or laser-like Smith-Purcell radiation is also generated above the grating via coupling and bunching of the electrons with the surface mode fields.

A device for the generation of ultrashort pulses, wherein an oscillator is formed by: a first and a second non-overlapping transmission band-pass filter, which can serve as reflecting end element of the oscillator; optically transparent means with non-linear Kerr coefficient χ.sup.(3) different from zero configured to achieve a spectral broadening by self-phase modulation of the signal transiting through these means; an optical waveguide that produces a positive gain; a node configured to receive a trigger signal designed to activate the operation of the oscillator; a trigger signal generating device comprising: a laser source, for example a microchip, configured to generate a laser pulse, preferably with a minimum bandwidth, having a duration of hundreds of ps, up to the ns; a coupling system designed to introduce the pulse of the trigger laser into a waveguide made of an optically transparent material characterised by a non-linear Kerr coefficient χ.sup.(3) different from zero, which is configured to produce two distinct effects in order to spectrally broaden the pulse of the trigger laser, and precisely: a) self-phase modulation four-wave mixing; the output of the waveguide supplies the trigger signal to the node. The pulses produced by the oscillator typically have a duration of the order of the picosecond and are easily reduced to the Fourier limit of circa 100 femtoseconds by means of a dispersive device.

A device for the generation of ultrashort pulses, wherein an oscillator is formed by: a first and a second non-overlapping transmission band-pass filter, which can serve as reflecting end element of the oscillator; optically transparent means with non-linear Kerr coefficient χ.sup.(3) different from zero configured to achieve a spectral broadening by self-phase modulation of the signal transiting through these means; an optical waveguide that produces a positive gain; a node configured to receive a trigger signal designed to activate the operation of the oscillator; a trigger signal generating device comprising: a laser source, for example a microchip, configured to generate a laser pulse, preferably with a minimum bandwidth, having a duration of hundreds of ps, up to the ns; a coupling system designed to introduce the pulse of the trigger laser into a waveguide made of an optically transparent material characterised by a non-linear Kerr coefficient χ.sup.(3) different from zero, which is configured to produce two distinct effects in order to spectrally broaden the pulse of the trigger laser, and precisely: a) self-phase modulation four-wave mixing; the output of the waveguide supplies the trigger signal to the node. The pulses produced by the oscillator typically have a duration of the order of the picosecond and are easily reduced to the Fourier limit of circa 100 femtoseconds by means of a dispersive device.

Optical frequency combs are used for a wide range of applications, some of which require precise control of the amplitude and phase of individual comb teeth. A technique is provided for tooth-level optical frequency comb control. A frequency comb may include a plurality of comb teeth that are separated from one another by a comb frequency spacing. This technique includes generating a train of control pulses, each of the control pulses being frequency-locked to a corresponding tooth of an optical frequency comb to be controlled. The tooth-level control of the frequency comb is enabled via stimulated Brillouin scattering using the train of control pulses.

An apparatus and a corresponding method for generating at least one random number are disclosed. The apparatus includes an optical parametric oscillator being pumped by a pump signal with a predetermined pump power and a predetermined pump frequency. The optical parametric oscillator is configured to operate in a period multiplication state for providing an oscillator output signal of alternating light pulses, the oscillator output signal having a period that is N-times the period of the pump signal, where N is an integer and N>I. The apparatus also includes a comparing unit being configured to compare the output signal with a reference signal, wherein the reference signal has a frequency that is 1/N of the predetermined pump frequency, and an evaluation unit being configured to generate the at least one random number based on the comparison of the output signal with the reference signal.

A tube preparation step of preparing a resin tube that has a tube wall impregnable with a solution including a fine substance and is made of a light-transmitting resin material, a solution preparation step of preparing a solution that includes a fine fluorescent substance that emits fluorescence or a fine scattering substance that scatters light as an oscillation material and an impregnation step of causing the resin tube to be immersed in the solution and causing the tube wall of the resin tube to be impregnated with the oscillation material, are included.